Creating WP Galleries from Dropbox (or alternative)?

I have to upload ~2gb of photos to a WP gallery I have and will be continually adding to them. Because I'll be hosting the same gallery on two sites (and because of the size), I was hoping I could use a site like Dropbox. My thinking was to upload them to Dropbox, then create a gallery from the images hosted on Wordpress, potentially through a plugin.

Unfortunately, I haven't found a way to do this nor a good alternative and was hoping someone here might have an idea.